1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) module, which is a kind of display device and, in particular, to an LCD module for use in a hand-held mobile phone.
2. Description of the Related Art
With development of wireless communication technology, hand-held mobile phones have been miniaturized and complicated. Accordingly, hand-held mobile phones are required to have high reliability in mechanical characteristics as well as in electrical characteristics.
For this reason, LCD module manufacturers have recently devised a measure for enhancing the strength of mold frames for protecting LCD panels.
A measure most widely used to enhance the strength of a mold frame is to attach a bent metal sheet, which is formed by bending a metal sheet, to the mold frame. Such a sheet called as chassis is typically formed from stainless steel. Stainless steel is widely used because it has significantly higher strength than the plastic material forming such a mold frame. In particular, it is the actual circumstances that problems with a portable phone caused by a mistake such as dropping or stepping on such a portable phone are considered as a barometer for evaluating the performance of the portable phone.
FIG. 1 schematically shows an LCD module for use in a typical hand-held mobile phone, and FIGS. 2 to 4 show a mold frame structure for use in a typical hand-held mobile phone. Referring to these figures, reference numeral 10 indicates an LCD panel, reference numeral 20 indicates a mold frame, and reference numeral 30 indicates a chassis.
In FIG. 1, the LCD panel 10 is received in the mold frame 20 and the chassis 30 is assembled to the mold frame 20 to increase the rigidity of the mold frame 20.
In FIGS. 2 and 3, the mold frame 20 is fabricated by injection-molding a plastic material, in which plural assembling projections 21 are formed on the lateral sides of the mold frame 20. The chassis 30 is fabricated by bending the edges of a thin metal sheet, in which the bent edges are formed with plural assembling holes 31, into which the assembling projections 21 are respectively inserted.
The mold frame 20 and the chassis 30 are assembled with each other by hooking the assembling projections 21 in the assembling holes 31 as shown in FIGS. 2 and 3. Here, the chassis 30 is used for the purpose of reinforcement for enhancing the rigidity of the mold frame 20.
With a typical LCD module as described above, however, because the chassis 30 is assembled with the mold frame 20 by way of the hooking structure between the assembling projections 21 and the assembling holes 31, the mold frame 20 and the chassis 30 cannot be completely coupled to one another due to an assembling tolerance or the like. Consequently, there is a problem in that a rigidity increasing effect as desired cannot be obtained and thus the LCD panel 10 cannot be stably supported.
In order to solve such a problem, LCD modules of double chassis structure with a top chassis added beyond a bottom chassis have been developed. However, such a module has not been employed very much because the top chassis provides only a slight increase in structural strength as compared to increasing the thickness and mass of such an LCD module.